As plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs) become more common, driver's may find it desirable to adjust their way of thinking about fuel (which can include conventional fuels and/or alternative fuels, such as, but not limited to, electricity) consumption.
For example, in a conventionally fueled (e.g., gasoline) vehicle, braking is typically tantamount to fuel consumption. In other words, when the vehicle is slowed, additional fuel is required to resume a previous speed, and no fuel is gained through the braking. But, with electric powered vehicles (including vehicles with partial electric power), regenerative braking can return some measure of lost velocity in the form of electric power. While the exchange is unlikely to be perfect, it may actually be desirable, for example, when a down-hill slope is capable of returning the vehicle to speed with little or no actual fuel usage.
In other instances, certain vehicle power systems may draw power from a fuel source and force a driver to adjust conventional notions about how fuel is consumed by using vehicle accessories (such as, but not limited to, HVAC systems, vehicle power outlets, etc.).
Adjusting a basic understanding of fuel usage may be difficult for a driver who has aligned their fuel-consumption-thinking to a certain paradigm over years of using a gasoline powered vehicle. Drivers are often loathe to thoroughly study vehicle manuals, and even if they are willing to do the reading, it may not be entirely clear where the paradigm has shifted.
Additionally, different vehicles (PHEVs, HEVs, BEVs, etc.) may respond differently to electrical system usage and driving performance, and it may be difficult for a driver to keep track of all the underlying potential variables on a vehicle-by-vehicle basis.